Goats

In Wildlife in Britain & Ireland Richard Perry writes:

It is possible that goats were indigenous in Britain, and they have certainly inhabited the hills of Wales and the Western Highlands for a very long time; but it is generally considered more likely that they were introduced as domestic stock by Neolithic tribes about 4000 BP... there are still feral herds in perhaps as amany as eighty localities in Scotland... The majority of these can be traced to stock that have escaped or have been turned out of domestic herds, for the billies are inveterate wanderers during the rutting season, travelling alone or in threes or fours up to fifty miles from their home range in search of the widely scattered bands of nannies: and domestic stock revert to the wild state in both habits and appearance very quickly, acquiring the characteristic long shaggy coat within as short a period as ten years of going feral. That only the hardiest strains shall survive is ensured by the kids being born during the severest winter weather from late January to late March.